This isn't usually a problem, but sometimes I don't get notifications for threads I'm subscribed to. The only such thread I know for sure is this one:

http://originaltrilogy.com/forum/topic.cfm/How-about-a-game-of-Japanese-Chess-ie-Shogi-darth-ender-vs-RicOlie-2-now-playing-Kyoto-Shogi-a-small-but-challenging-unpredictable-variant/topic/16176/page/24/

Sometimes I get notifications, sometimes I don't. I haven't noticed any definite patterns, but it seems to happen when I am already in the Off Topic forum, so it isn't a real problem. I just thought I should mention it though, in case it is some kind of glitch with that thread.